Conventional gas turbine engines include rotor blades which are removably mounted to respective rotor discs. The disc and blade fixings of a rotor assembly of gas turbine engines, particularly of the high pressure turbine rotor assembly, conventionally comprise an undulating or “firtree” shaped profile in order to meet the requirements of engine performance, weight reduction, secondary air consumption, disc/blade life considerations, etc.
The prior art is replete with attempts to reduce or compensate for the inherent stresses in the discs, created during the disc's manufacture, the formation of the blade fixing slots and/or the placement of the blade roots in the dovetail slots. However these solutions remain complicated and somewhat lacking.
Accordingly, there is a need to provide an improved method and apparatus for providing such discs.